Epson S1C63558 - Manual (Page 107)

S1C63558 TECHNICAL MANUAL EPSON 97
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Serial Interface)
During receiving
The received data is stored.
When "1" is read: High level
When "0" is read: Low level
The data from the receive data buffer can be read out.
Since the sift register is provided separately from this buffer, reading can be done during a receive opera-
tion in the asynchronous mode. (The buffer function is not used in the clock synchronous mode.)
Read the data after waiting for a receive completion interrupt.
When performing parity check in the 7-bit asynchronous mode, "0" is loaded into the 8th bit (TRXD7/
TRXD7S) that corresponds to the parity bit.
The serial data input from the SIN terminal is level converted, making the High (V
DD ) level bit "1" and
the Low (V SS ) level bit "0" and is then loaded into this buffer.
At initial reset, the buffer content is undefined.
OER: Serial interface (1) overrun error flag (FF73H•D0)
OERS: Serial interface (2) overrun error flag (FF5BH•D0)
Indicates the generation of an overrun error.
When "1" is read: Error
When "0" is read: No error
When "1" is written: Reset to "0"
When "0" is written: Invalid
OER/OERS is an error flag that indicates the generation of an overrun error and becomes "1" when an
error has been generated.
An overrun error is generated when a receiving of data has completed prior to writing "1" to RXTRG/
RXTRGS in the asynchronous mode.
OER/OERS is reset to "0" by writing "1".
OER/OERS is set to "0" at initial reset or when RXEN/RXENS is set to "0".
PER: Serial interface (1) parity error flag (FF73H•D1)
PERS: Serial interface (2) parity error flag (FF5BH•D1)
Indicates the generation of a parity error.
When "1" is read: Error
When "0" is read: No error
When "1" is written: Reset to "0"
When "0" is written: Invalid
PER/PERS is an error flag that indicates the generation of a parity error and becomes "1" when an error
has been generated.
When a parity check is performed in the asynchronous mode, a parity error will be generated if data that
does not match the parity is received.
PER/PERS is reset to "0" by writing "1".
PER/PERS is set to "0" at initial reset or when RXEN/RXENS is set to "0".